1. Login to Sametime System Console
2. Navigate to Sametime System Console -> Sametime Meeting Servers
3. Click On 'Deployment Identifier"
4. On 'Server Configuration' Page, click on 'Edit' button
5. Find the Configuration Key 'webextension.ff.enabled' and set it to true
6. Find the Configuration Key "webplayer.chrome.mac.enabled" and set it to "true"
7. Find the Configuration Key "webplayer.chrome.windows.enabled" and set it to "true"
8. Click on Apply.

(If any of the three keys mentioned above are not present, add them and make sure the value is set to "true" for all and click "Apply").

Restart Sametime Meeting server and Sametime Proxy server.

FIXES INCLUDED IN THIS HOTFIX

Mozilla is removing support for the NPAPI based plug-ins in Firefox starting with version 52 (non-ESR). IBM is moving towards supporting Web extension-based add-ons. This fix provides Firefox Native Messaging Host Support for Enterprise Customers.

**NOTE 2: This hotfix is required only for the customers using Firefox 52 (non-ESR version) and above. Customers can keep using other supported browsers like Internet Explorer, Chrome, Safari, Firefox ESR versions, without any issues, if they don't install this hotfix.